$ sudo groupadd docker
$ sudo usermod -a -G docker ${USER}
$ sudo service docker restart
# To prevent log out and log back in again,# to pick up the new docker group permissions on the current bash session
$ newgrp docker

Docker’s overlay network driver supports multi-host networking natively out-of-the-box.
This support is accomplished with the help of libnetwork, a built-in VXLAN-based overlay network driver,
and Docker’s libkv library.